And although it is viral, and rather comical to see how one might age, you may want to think twice before using FaceApp.

FaceApp first went viral in 2017, gaining millions of users. The app recently gained popularity again after #faceappchallenge posts took over social media and celebrities, along with everyone else, began posting photos using the app's old-age filter.

But according to Forbes, a security researcher who goes by the pseudonym Elliot Alderson downloaded the app and checked where it was sending users' faces. The French cyber expert found FaceApp only took submitted photos - those that you want the software to transform - back up to a company server, not all your photos.

He also found the server is based in America, not Russia. But, given the developer company is based in St. Petersburg, the faces will be viewed and processed in Russia. It's unclear how much access FaceApp employees have to those images and Forbes hadn't received comment from the company about just what it does with uploaded faces.

Privacy Policy

Although there is no evidence to support privacy concerns, FaceApp's privacy policy doesn't exactly offer many assurances.

The FaceApp's privacy policy states it also collects location data and users' browsing history.

"These tools collect information sent by your device or our Service, including the web pages you visit, add-ons, and other information that assists us in improving the Service," the policy states.

And though it states that "we will not rent or sell your information to third parties outside FaceApp," it explicitly said that it does share information with "third-party advertising partners," in order to deliver targeted ads.

Forbes suggests users who are concerned about the app having permission to access any photos at all might want to look at all the tools they have on their smartphone. It's likely many have access to photos and an awful lot more. Your every move via location tracking, for instance. To change permissions, either delete the app, or go to app settings on your iPhone or Android and change what data tools are allowed to access.

FaceApp CEO Yaroslav Goncharov has not yet responded to questions about the company's privacy policy. He promised Forbes a statement later Wednesday.